• Current Optics and Photonics
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• 제8권3호
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• pp.215-224
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• 2024

In medium- and long-range optical imaging systems, atmospheric turbulence causes blurring and distortion of images, resulting in loss of image information. An image-restoration method based on an adaptive feature-fusion multi-input-multi-output (MIMO) dense U-shaped network (Unet) is proposed, to restore a single image degraded by atmospheric turbulence. The network's model is based on the MIMO-Unet framework and incorporates patch-embedding shallow-convolution modules. These modules help in extracting shallow features of images and facilitate the processing of the multi-input dense encoding modules that follow. The combination of these modules improves the model's ability to analyze and extract features effectively. An asymmetric feature-fusion module is utilized to combine encoded features at varying scales, facilitating the feature reconstruction of the subsequent multi-output decoding modules for restoration of turbulence-degraded images. Based on experimental results, the adaptive feature-fusion MIMO dense U-shaped network outperforms traditional restoration methods, CMFNet network models, and standard MIMO-Unet network models, in terms of image-quality restoration. It effectively minimizes geometric deformation and blurring of images.

• IEIE Transactions on Smart Processing and Computing
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• 제6권3호
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• pp.168-174
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• 2017

Videos recorded on surveillance cameras or by car black boxes at night have distorted images due to illumination variation. Therefore, it is difficult to analyze morphological characteristics of objects, and it is limiting to use such distorted images as evidence in traffic accidents. Image restoration is performed by amplifying the brightness of nighttime images using linearized gamma correction to increase their contrast (which destroys visual information) and by minimizing degradation factors caused by irregular traveling.

• 충청수학회지
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• 제25권2호
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• pp.367-377
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• 2012

The goal of the image restoration is to find a good approximation of the original image for the degraded image, the blurring matrix, and the statistics of the noise vector given. Fast truncated Lagrange (FTL) method has been proposed by G. Landi as a image restoration method for large-scale ill-conditioned BTTB linear systems([3]). We implemented FTL method for the image restoration problem with reflective boundary condition which gives better reconstructions of the unknown, the true image.

• 한국방사선학회논문지
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• 제13권3호
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• pp.453-458
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• 2019

본 연구에서는 Geant4 application for tomographic emission (GATE) 시뮬레이션 프로그램을 통해 설계 된 male adult mesh (MASH) 팬텀의 영상을 획득한 후 다양한 필터링 인자가 설정된 FNLM 노이즈 제거 알고리즘을 적용함으로써 그에 따른 영상 특성의 경향성을 알아보고자 한다. 이를 위해 GATE 시뮬레이션 프로그램을 통해 인체를 모사할 수 있는 MASH 팬텀을 설계하였다. 또한, 설계된 MASH 팬텀을 기반으로 MATLAB 프로그램을 통해 복부영상을 획득한 후 0.005의 $\sigma$ 값을 갖는 Gaussian noise를 추가하여 열화영상을 모델링하였다. 모델링 된 열화영상으로부터 제안하는 FNLM 노이즈 제거 알고리즘의 필터링 인자를 각각 0.005, 0.01, 0.05, 0.1, 0.5, 1.0 으로 설정하여 적용하였으며, 정량적 평가를 위해 FNLM 노이즈 제거 알고리즘이 적용된 영상들로부터 각각의 coefficient of variation (COV), signal to noise ratio (SNR) 그리고 contrast to noise ratio (CNR)을 측정하였다. 결과적으로, 0.05의 필터링 인자가 적용된 영상에서 가장 개선된 COV, SNR 그리고 CNR 값을 보였다. 특히, COV는 설정된 필터링 인자가 증가함에 따라 감소하였으며, 0.05 값 이후부터 거의 일정한 값을 나타내었다. 또한, SNR 및 CNR의 경우 필터링 인자가 증가함에 따라 증가하였으며, 0.05 값 이후부터 감소하는 경향을 보였다. 결론적으로, 열화 영상으로부터 FNLM 노이즈 제거 알고리즘 적용 시 적합한 필터링 인자를 설정해야 함이 증명되었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
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• pp.13-16
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• 2001

In the Dedicated Short Range Communication (DSRC) system channel, a large number of bit errors occur because of Additive White Gaussian Noise (AWGN) and fading. When an image data is transmitted under the condition, reconstructed image quality is significantly degraded. In this paper, as an alternative to the error correcting code and/or automatic repeat request scheme, we propose an error recovery scheme for image data transmission. We first analyze how transmission errors in the DSRC system channel degrade image quality. Then, in order to improve image quality, we propose error resilient and concealment schemes for still image transmission using DCT-based fixed length coding, hamming code, cyclic redundancy check, and interleaver. Finally, we show its performance by an experiment.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1478-1481
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• 2007

This paper introduced a measurement method for image sticking based on human vision perception. Existing image sticking quantification method is mostly different from visible level by human perception. It takes a long time to measure image sticking which is degraded by time due to using a spot photometer, therefore many test samples could not be evaluated in a given short period of time in mass production line. However, the new measurement method in this paper is possible to evaluate a large quantity of samples in fast and high correlation with human perceptual level of image sticking.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.863-864
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• 2008

To predict the iris matching performance and guarantee its reliability, image quality measure prior to matching is desired. An analysis on iris image degradation factors which deteriorate matching performance is a basic step for iris image quality measure. We considered five degradation factors-white-out, black-out, noise, blur, and occlusion by specular reflection-which happen generally during the iris image acquisition process. Experimental results show that noise and white-out degraded the EER most significantly, while others on EER were either insignificant or degradation images resulted in even better performance in some cases of blur. This means that degradation factors that affect the performance can be different from those based on human perception or image degradation evaluation.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.859-862
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• 2008

We have realized static image on organic light emitting diodes (OLEDs) using photoluminescence degradation. Ultraviolet (UV) was irradiated to the glass side of device. UV power was 350 Wand the wavelength was 365 nm. The UV irradiation gives rise to the degradation of photoluminescence. Due to the degradation, the current density-voltage curve was shifted to the higher voltage side and the luminescence was also degraded by the current and photoluminescence drop. The negative imaged films were prepared to control the transmittance of UV. The UV light was passed through the film. By this method, the film image was transferred to the device with reversed image and the static image was realized on the OLED.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.298-300
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• 2005

Satellite payload on-board date compression unit are use for saving date storage space and reducing time to transmit payload data to the ground station. The KOMPSAT-3 payload will generate higher data rate than KOMPSAT-2 due to its better ground sample distance capacity. High input data rate and limited output transmission data rate might lead excessive compression and degraded image quality. This paper presents a trade-off study about data storage capacity and compression parameters for estimated KOMPSAT-3 system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.485-488
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• 2003

A conventional correlation target tracker is analysed with a simple mathematical approach. And, we will propose a correlation measure with selective attentional property in order to overcome the false-peak problem of the conventional methods. Various experimental results show that the proposed correlation measure is able to reduce considerably the probability of false-peaks degraded by the correlation between background images of a reference block and a distorted and noisy sensor input image.